Chrysler 9.25 Fluid Type

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Braeden Clark

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So I am hearing some noise and I'm thinking it may be coming from my rear end. I want to inspect it and refill it with new fluid. What type do I use for the Chrysler 9.25? Would I use 2 quarts of 75w-90 and then fill the rest with a lsd additive?

Also how expensive would it be to have a 9.25 rebuilt at a shop? Just because... I have a bad feeling.
 
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pacofortacos

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Use synthetic 75w-90 or higher with the limited slip additive already in it.
I really like Redline but it is harder to find locally.
Most already have the additive in the oil but check to be sure. Valvoline syn power would work.

Is your noise a whine or a chatter on turns??
 
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Braeden Clark

Braeden Clark

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Use synthetic 75w-90 or higher with the limited slip additive already in it.
I really like Redline but it is harder to find locally.
Most already have the additive in the oil but check to be sure. Valvoline syn power would work.

Is your noise a whine or a chatter on turns??

Sounds like this. Maybe not quite as loud but similar. I think. I wish the guy would commented what it ended up being but any opinions? Eventually here I am going to jack it up and make sure it's coming from the dif. As a side note I just bought this truck and drove it 13 hours home. No issues. Until I heard this in the last 5 minutes
 

pacofortacos

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Step one - pull the plug on the rear cover and make sure it has fluid in it.

High pitch whine is usually pinion bearing, slightly slower whine like in the video - is usually carrier or axle bearing IF it isn't something with emergency brake system.

If it is in turns only it's often a LSD problem.

Pull the rubber plug and there should be oil within 1/4" or so of the bottom of the plug hole, also it should be fairly decent looking - too clean and he probably just changed it to cover a problem, too dark and it is probably original or used hard, also after you drain it, you can often use a magnet to look for metal particles. A bunch of metal flakes = bad.
 
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Braeden Clark

Braeden Clark

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1999
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Step one - pull the plug on the rear cover and make sure it has fluid in it.

High pitch whine is usually pinion bearing, slightly slower whine like in the video - is usually carrier or axle bearing IF it isn't something with emergency brake system.

If it is in turns only it's often a LSD problem.

Pull the rubber plug and there should be oil within 1/4" or so of the bottom of the plug hole, also it should be fairly decent looking - too clean and he probably just changed it to cover a problem, too dark and it is probably original or used hard, also after you drain it, you can often use a magnet to look for metal particles. A bunch of metal flakes = bad.
Well I pulled the plug. It definitely had oil in it. Because it came pouring out. Unfortunately it did look a little shiny. I guess my next step will be to drain it all and inspect. Unfortunately
 
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Braeden Clark

Braeden Clark

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Step one - pull the plug on the rear cover and make sure it has fluid in it.

High pitch whine is usually pinion bearing, slightly slower whine like in the video - is usually carrier or axle bearing IF it isn't something with emergency brake system.

If it is in turns only it's often a LSD problem.

Pull the rubber plug and there should be oil within 1/4" or so of the bottom of the plug hole, also it should be fairly decent looking - too clean and he probably just changed it to cover a problem, too dark and it is probably original or used hard, also after you drain it, you can often use a magnet to look for metal particles. A bunch of metal flakes = bad.
The only thing giving me a little hope is that it's not a super constant noise. So I'm praying it may be something with the e brake system... I would love if that was it...
 

pacofortacos

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Take some of the fluid in a pan and see if a magnet affects the shine - if it is metal, it will usually do something in the presence of a magnet.
 

pacofortacos

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If it was over full, it might have just aerated the oil some and caused a noise.
 
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Braeden Clark

Braeden Clark

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Use synthetic 75w-90 or higher with the limited slip additive already in it.
I really like Redline but it is harder to find locally.
Most already have the additive in the oil but check to be sure. Valvoline syn power would work.

Is your noise a whine or a chatter on turns??
Update on the noise. I jacked up the rear of the truck and put it in drive. The noise seems to come from something on the passenger rear. Sounds like the brakes are dragging or e brake is dragging. Only thing that confuses me is I could take the drum off rather easily. Maybe it's barely dragging, but just enough to make the noise. Nothing looked abnormal. Anything back there that isn't brake related that could be making a noise?
 

pacofortacos

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There is an axle bearing right there near the end of the axle.
Is it possible someone put the shoes on in reverse - the drum doesn't usually come off easily.
 

Bear_Gibson

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Those adjusters are notorious for not working right. Try running it without wheels and the drum. Like Paco said, there is a roller bearing that the axle rides on just behind the brakes.
 
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Braeden Clark

Braeden Clark

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Those adjusters are notorious for not working right. Try running it without wheels and the drum. Like Paco said, there is a roller bearing that the axle rides on just behind the brakes.
Well I pulled the rear dif cover and found a bunch of destruction. Not to mention my pinion bearing is noisy. So now I have decided to swap the whole rear differential for a used one with lower miles. Biggest issue is that my gear ratio (3.92) is impossible to find in second gen 9.25s. I am going to buy a 3rd gen 9.25 with the correct ratio and move the perches and mod the brake and e brake lines. Cheaper for me. Even if it sucks that it's necessary.
 
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